These diseases include emphysema, chronic bronchitis, and sometimes asthma. Certain diseases that cause bronchiectasis also lead to chronically obstructed lung airways. People who’ve been diagnosed with COPD typically have emphysema, chronic bronchitis, or both.

Everyone who’s diagnosed with emphysema is said to have COPD. However, it’s possible to be diagnosed with COPD and not have emphysema. A person can receive a COPD diagnosis while only having chronic bronchitis, for instance.

Emphysema is usually the direct result of years of smoking cigarettes. Its symptoms tend to affect people who are middle-aged or older. Chronic bronchitis, which can occur earlier or later in life, can also be caused by tobacco smoking.

Your lungs trap pollutants with a thin layer of mucous coating. Tiny brushes known as cilia sweep away the harmful particles so that they can be removed from your lungs. When you cough, dirt and pollutants are brought up with the mucus.

Because smoking destroys the cilia, your lungs can’t work properly — there’s no proper way for the particles to get out. This results in damage to the tiny air sacs in the lungs called alveoli. This damage occurs in people with emphysema.

Inflammation caused by smoking can lead to chronic bronchitis and damage the breathing tubes and bronchi, even though the alveoli may not yet be damaged permanently.

Effect on the alveoli

Think of the alveoli like tiny clusters of balloons. They inflate and deflate when you breathe. When the alveoli become damaged, however, they lose their ability to recoil properly. This in turn makes it difficult to breathe.

As alveoli become permanently stretched and their walls rupture, the lungs will have trouble taking in oxygen and breathing out carbon dioxide. This forces the heart and lungs to work harder and decreases the oxygen available to other organs and tissues, causing further damage.

People who inhale fumes from fuels burned for cooking or have extended exposure to pollutants, such as workplace or environmental hazards, can also develop COPD. It’s also believed that genes may play a role in who develops COPD and how severe it is.

Anyone who has COPD or wants to prevent it needs to give up smoking immediately. According to the Centers for Disease Control and Prevention (CDC), smoking causes up to 80 percent of all COPD-related deaths.

Little is known about how electronic cigarettes, also called e-cigarettes, exactly affect the lungs and whether they contribute to COPD or other lung diseases.

In addition to nicotine, the vapor in e-cigarettes can also contain heavy metals, superfine debris, and cancer-causing substances, including one called acrolein.

Many e-cigarette companies label their aerosols and flavorings as ingredients that are “generally regarded as safe,” but that is based on research about ingestion and swallowing of these substances in food, not inhalation.

More studies are needed to determine the full impact and potential risks that e-cigarettes pose to humans.

Although e-cigarettes are often marketed as a way to quit smoking in the traditional sense, the U.S. Food and Drug Administration (FDA) hasn’t approved this use. In 2016, the FDA announced it would begin regulating the manufacture, import, packaging, advertising, and sale of e-cigarettes in the United States.

COPD can usually be prevented by maintaining healthy habits. However, it remains the third leading cause of death in the United States. COPD affects around 30 million people throughout the country.

In addition to quitting smoking or never picking up the habit, you can protect your lungs by avoiding pollutants. If you work in an environmentally hazardous job, discuss safety measures with your supervisor.